Unguided artillery rockets, utilized for area suppression fire missions, are most vulnerable to trajectory perturbations during launch and the first several seconds of flight. The trajectory perturbations are manifested as dispersion of the rockets over the target area, with the result that many such rockets must be fired to ensure that the area of interest is sufficiently covered.
Efforts have been made to add low or medium cost guidance packages to such ballistic rockets to make them impact the selected target more accurately. One system, intended for small and short range rockets, included a semi-active laser seeker and canard guidance package for direct fire guidance all the way to the target. Another system, focusing on large indirect fire artillery rockets for longer ranges, utilized Global Positioning System inputs to an inertial measurement unit along with nose-mounted canards for trajectory control.
However, such efforts required the development of a new airframe for the rockets. Further, both systems placed the control actuators and the associated electronics in the nose of the weapon and controlled the trajectory all the way until target impact. Even though these systems rendered such rockets more accurate against point or very much smaller objects than area targets, neither system is suitable for use with the large stocks of unguided artillery rockets that are already in existence, because of the incompatibility with the rockets' airframe.